# 单例模式
class Singleton:

    # 类属性
    # 私有类属性 = 类属性值
    __instance = None

    def __new__(cls, *args, **kwargs):
        if not cls.__instance:
            cls.__instance = super().__new__(cls)
        return cls.__instance


s1 = Singleton()
print(s1)

print(Singleton())